: Stereotaxic neurosurgical techniques and baroreflex challenges will be employed in the chronically-instrumented fetal sheep to surgically disconnect the PVN to evaluate the extent to which and the mechanisms by which the late gestation fetal sheep PVN: (1) modifies normal development of brainstem and sympathetic preganglionic neuron regulation of peripheral vascular tone; and (2) is a site for production of glucocorticoid-induced hypertension.